In the photographic systems which are currently abundant, a silver halide color light-sensitive material for photography (a color negative film) is loaded into a camera for photographing and a color photographic paper is printed from a so-called color negative film developed to obtain a positive color print (a negative-positive system). Alternatively, in a reversal processing type silver halide color light-sensitive material (a color reversal film) for photographing, a positive image can be obtained only with reversal developing. Therefore, it is viewed as it is or is viewed with a slide projector. In addition, a positive color print can be made (a positive-positive style). However, since the color reversal film has narrow photographing latitude, it is not suitable for easy photographing. In addition, a positive color print is expensive. Therefore, aforesaid positive-positive system has not got ahead of aforesaid negative-positive system. In addition, due to appearance of a photo-taking unit housing an unexposed color negative film with a photographable state, i.e., a so-called lens-fitted film, opportunity of photographing a color negative film has further increased. Accordingly, the position of the negative-positive type has been solidified.
Among proliferation of aforesaid color photographic system, a black-and-white silver halide light-sensitive material for photographing has caused a calm boom. It is assumed that, in the overflow of color photography, a monochrome image is felt to be fresh in return and that its peculiar description is felt to be mysterious. The main users of the black-and-white light-sensitive material for photography was a professional and advanced amateur. However, in April, 1995, "Film In-Mini B & W" was released, enabling any people to be able to enjoy photographing using a black-and-white silver halide light-sensitive material. Since it obtained unexpected reputation, the photographic industry field had to take notice of.
However, since the photographic processing method of the black-and-white silver halide light-sensitive material for photographing is different from that of a negative-positive type color photographic system which has been proliferating. Therefore, there is a big trouble to labs in the city to select the black-and-white silver halide light-sensitive material to handle. In addition it is necessary to newly install a photographic processing steps for the black-and-white silver halide light-sensitive material.
On the contrary, a monochrome image forming silver halide light-sensitive material for photographing which is suitable for the photographic processing of a commonly-prevailing negative-positive type color photographic system is known. In U.S. Pat. Nos. 2,592,514 and 4,348,474, Japanese Patent Publication No. 59136/1988 and Japanese Patent Open to Publication (hereinafter, referred to as Japanese Patent O.P.I. Publication) No. 236550/1986, a monochrome image forming silver halide light-sensitive material using a black coupler is disclosed.
U.S. Pat. Nos. 2,181,944, 2,186,736, 4,368,255, 5,141844 and Japanese Patent O.P.I. Publication Nos. 56838/1982, 58147/1982, 215645/1983, 107144/1991, 214357/1994 and 199421/1995 and Japanese PCT Application Publication No. 505580/1994 disclose technologies to form a black dye image by mixing a yellow coupler, a magenta couple and a cyan coupler which are used for a conventional silver halide color light-sensitive material. However, all of the above-mentioned technologies have a shortcoming that printing onto a photographic paper is complicated though photographic processing can be commonalized. If the above-mentioned technologies are used for color photographic processing, either coloring component collapses balance with other coloring components due to difference of coupler reactivity. Therefore, it was difficult to obtain neutral gray throughout the entire density regions. In addition, processing fluctuation occurred due to developing agent density, pH, temperature and contamination so that it was extremely difficult to stably form a monochrome image. Even in the case of a black-and-white printing, its color tone of final image has warmth and nostalgic sepia tone is favored. It is demanded to easily prepare a monochrome printing in the above-mentioned sepia tone.
On the other hand, in a silver halide color light-sensitive material widely prevailing, a two-equivalent coupler having a favorable coloring property is known as one of a technology which improves sharpness. However, by the use of the above-mentioned means, graininess extremely deteriorates and fogging also increases though sharpness is increased.
An objective of the present invention is to provide a silver halide light-sensitive material which is suitable for a negative-positive system color photographic processing, which is excellent in terms of graininess and processing stability and, simultaneously, which is easy for printing onto a photographic paper and by which sepia tone monochrome printing is easily prepared, a monochrome image forming silver halide light-sensitive material, a photo-taking unit and a monochrome image forming method.